Piers, wharves and docks are utilized throughout the world to moor or berth vessels of all types. particularly in the case of larger vessels, such piers and wharves undergo constant battering from the vessels whenever they dock or depart at the port. As a consequence of such battering, pier, wharf and dock maintenance and repair operations have become both expensive and time consuming.
In addition, accidents involving vessels and piers during docking procedures are all too often a frequent occurrence, contributing even further to the expense of repairing and maintaining adequate docking facilities for vessels of the armed forces and civilian services. It is therefore evident that the use of some sort of pier cushioning system is mandated if pier repair and maintenance are to be controlled.
Pier cushioning systems are not new per se and have been used almost as long as piers themselves. Prior pier cushioning systems have included piles of timber, steel, reinforced concrete and pre-stressed concrete, timber hung systems, retractable fender systems, rubber fender systems, gravity-type fender systems and cushioning devices as exemplified in U.S. Pat. Nos. 4,662,791, 4,650,371, 4,137,861 and 4,135,467.
Prior pier cushioning systems have had inherent difficulties, however, such as low energy absorption capacity, biodeterioration of the construction material utilized in the cushioning system, vulnerability to corrosion, unsuitability at locations with significant tide and current effects, inability to be utilized with varying size vessels and high initial costs. Most importantly, however, prior pier cushioning systems have not eliminated the high maintenance and repair costs now associated with keeping a pier in operating condition.
The present invention provides an efficient hydraulic cylinder pier cushioning system having the unique ability to determine the mass and velocity of docking vessels. In practice, use of the invention alleviates much of the high maintenance and repair costs due to pier damage. Additionally, the present pier cushioning system may be utilized with any size vessel or at any location regardless of tide or weather conditions.